Cys-beta-Amyloid (1-42)

Product Name: Cys-beta-Amyloid (1-42)

Sequence One Letter Code: CDAEFRHDSGYEVHHQKLVFFAEDVGSNKGAIIGLMVGGVVIA

Sequence Three Letter Code: H-Cys-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-Leu-Val-Phe-Phe-Ala-Glu-Asp-Val-Gly-Ser-Asn-Lys-Gly-Ala-Ile-Ile-Gly-Leu-Met-Val-Gly-Gly-Val-Val-Ile-Ala-OH

Chemical Formula:C206H316N56O61S2

Molecular Weight: 4617.6

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C

Research Area: Alzheimer's Disease

Source / Species: human

Conjugation: Unconjugated

Code Nacres: NA.26

Application: Cys-β-Amyloid (1–42) is a cysteine-modified variant of the Aβ(1–42) peptide, the principal amyloid species associated with senile plaque formation in Alzheimer’s disease. The Aβ(1–42) sequence exhibits strong aggregation propensity and accumulates within neuronal tissue, contributing to synaptic dysfunction and neurotoxicity. Introduction of a cysteine residue enables site-specific conjugation and disulfide-mediated crosslinking, allowing researchers to control peptide labeling, immobilization, or aggregation studies. This modified peptide is widely used as a model system for investigating amyloid assembly, oligomer formation, and aggregation mechanisms. Cys-β-Amyloid (1–42) is therefore an important research tool for exploring the molecular basis of amyloid toxicity and structure–function relationships in Alzheimer’s disease.

Current Research: Cys-β-Amyloid (1–42) is a modified form of the human amyloid-β peptide Aβ(1–42) in which a cysteine residue is incorporated to enable chemical conjugation and controlled crosslinking. The native Aβ(1–42) peptide is widely recognized as one of the principal amyloid species associated with senile plaque formation in Alzheimer’s disease, where it accumulates in brain tissue and contributes to neuronal dysfunction. Because of its strong tendency to aggregate into oligomers and fibrils, Aβ(1–42) has become a central model peptide for studying protein misfolding and amyloid formation. The introduction of a cysteine residue provides additional experimental flexibility. The thiol group of cysteine allows site-specific labeling, immobilization, and disulfide-mediated crosslinking, making Cys-β-Amyloid (1–42) particularly useful for controlled biochemical and biophysical experiments investigating amyloid assembly and toxicity. Amyloid-β Peptides in Neurodegenerative Research Amyloid-β peptides originate from the amyloid precursor protein (APP) through sequential cleavage by β-secretase and γ-secretase enzymes. This process generates peptides of different lengths, among which Aβ(1–40) and Aβ(1–42) are the most studied. Although Aβ(1–40) is more abundant overall, Aβ(1–42) displays a stronger tendency to aggregate, forming oligomeric assemblies and fibrillar structures that accumulate in amyloid plaques. These aggregates are strongly associated with pathological features observed in Alzheimer’s disease, including: Formation of extracellular amyloid plaques Disruption of neuronal communication Activation of inflammatory responses in the brain Induction of oxidative and cellular stress Because of these characteristics, Aβ(1–42) is widely used as a model system for exploring the molecular basis of amyloid aggregation and neurotoxicity. Aggregation Behavior of Aβ(1–42) Aβ(1–42) is particularly prone to self-assembly into ordered aggregates, a process that involves multiple structural transitions. The peptide can form a range of aggregated species, including soluble oligomers, protofibrils, and mature amyloid fibrils. The aggregation process generally progresses through several stages: Monomer formation – individual peptide molecules in solution Oligomerization – formation of small soluble assemblies Protofibril development – elongated intermediate structures Fibril formation – highly ordered β-sheet–rich fibrillar aggregates Many studies focus on understanding how these structural states contribute to amyloid toxicity and neuronal dysfunction. Role of Cysteine Modification In Cys-β-Amyloid (1–42), the addition of a cysteine residue introduces a reactive thiol group, which provides a convenient site for chemical modification. Cysteine residues are commonly used in peptide design because their thiol side chains enable highly selective reactions. This modification supports several experimental strategies, including: Site-specific labeling with fluorescent probes Attachment of reporter molecules or affinity tags Immobilization on surfaces for structural studies Controlled disulfide crosslinking to stabilize peptide assemblies These capabilities allow researchers to design experiments that precisely control peptide interactions and aggregation behavior. Studying Amyloid Assembly and Oligomer Formation Cys-β-Amyloid (1–42) is frequently used in experiments investigating the mechanisms of amyloid assembly. The cysteine modification allows researchers to manipulate peptide interactions in ways that are not possible with the native sequence. For example, disulfide bonds can be used to stabilize specific aggregation states or to create defined oligomeric structures. These stabilized assemblies are valuable for studying how different aggregate forms influence cellular responses. Researchers use this peptide to explore: Early steps in amyloid oligomer formation Structural features of peptide aggregates Factors that influence aggregation kinetics Interactions between amyloid peptides and other biomolecules Such experiments help clarify how amyloid peptides transition from soluble monomers to aggregated structures. Applications in Alzheimer’s Disease Research Because Aβ(1–42) is strongly associated with plaque formation in Alzheimer’s disease, modified peptides such as Cys-β-Amyloid (1–42) are widely used in studies aimed at understanding the molecular mechanisms underlying amyloid-related neurodegeneration. Experimental applications include: Investigating structure–function relationships of amyloid peptides Studying aggregation-induced cellular stress responses Characterizing peptide interactions with membranes or proteins Developing experimental models of amyloid toxicity By enabling precise labeling and controlled crosslinking, cysteine-modified variants help researchers examine amyloid behavior with greater experimental control. A Versatile Tool for Protein Misfolding Studies Beyond Alzheimer’s research, amyloid-β peptides are widely used as model systems for studying protein misfolding and aggregation, processes that occur in many neurodegenerative disorders. Cys-β-Amyloid (1–42) provides additional experimental flexibility, allowing scientists to track peptide interactions and structural changes using biochemical and imaging techniques. This versatility makes the peptide valuable for research areas such as: Amyloid fibril formation mechanisms Structural characterization of protein aggregates Peptide–membrane interactions Experimental studies of aggregation dynamics Conclusion Cys-β-Amyloid (1–42) is a cysteine-modified variant of the amyloid-β peptide Aβ(1–42), a key component of amyloid plaques associated with Alzheimer’s disease. The strong aggregation propensity of Aβ(1–42) makes it a widely used model for studying amyloid formation and protein misfolding. By introducing a cysteine residue, this modified peptide enables site-specific conjugation, labeling, and disulfide-mediated crosslinking, providing researchers with additional tools for controlling and analyzing peptide assembly. As a result, Cys-β-Amyloid (1–42) plays an important role in investigations of amyloid aggregation mechanisms, oligomer formation, and the molecular basis of amyloid-related neurotoxicity.